Natural energy resources offer low pollution, high regeneration, and easy collection. Wind and solar energy are two ideal natural energy resources compared to coal, petroleum, and gas for thermal energy generation (which have limited quantities and are highly pollutive) and water for hydraulic energy generation (which is restricted by the terrain). Particularly, a stable and continuous energy supply can be ensured if different natural energy resources are combined.
In recent years, application of solar energy in energy generation has been increasing significantly. Solar panels are broadly deployed by various manufacturers to reduce the cost in power consumption and set up an environment-friendly manufacturing site. How to effectively convert a natural energy into electricity and store it has become one of the major subjects in today's energy and resources research. A light emitting device which uses solar energy as its power supply is disclosed in U.S. Pat. No. 6,994,448.
However, electric energy is the essential element for driving electronic devices and appliances. Conventionally, electric energy is generated by using thermal energy, hydraulic energy, or nuclear energy and then conducted to electronic devices and appliances to charge the same through transformers, power cables, and receptacles. Since the conventional technique for driving electronic devices and appliances depends on the contact between different elements, the charging effect may not be satisfactory due to oxidized contact points and sparks, electric shocks, power failures may be caused. In addition, different electronic devices and appliances require different power cables and charge apparatuses. Thus, the cables may be tangled together if different electronic products are used, and the working area of these electronic products may be limited by the position of the power source and the lengths of the cables.
Some wireless charging techniques have been developed in recent years. For example, an optical charge apparatus including a light source and a sensor connected to the light source is disclosed in U.S. Patent Publication 2007/0114967. When the sensor detects that a portable electronic apparatus having photovoltaic cells as its receiving device is getting close to the light source, the sensor controls the light source to emit light. The light emitted by the light source reaches the photovoltaic cells in the portable electronic apparatus to charge the portable electronic apparatus. However, because the photovoltaic cells are used as the receiving end of the energy transmission, this charge apparatus disclosed in the U.S. Patent Publication 2007/0114967 has a low photoelectric conversion rate therefore is not so practical.
A non-radiative energy wireless transmission technique is disclosed in PCT Publication WO 2007/008646 A2, wherein the energy is transmitted through resonance coupling between two resonance structure apparatuses.
Additionally, a wireless energy transmission system is disclosed in U.S. Patent Publication 2006/0266917, wherein an energy signal is issued and the position of an electronic product to be charged is determined at the receiving end through a reflection mechanism so as to charge the electronic product. A wireless charging system adaptable to a vehicle is disclosed in U.S. Pat. No. 5,982,139. When the wireless charging system receives a positioning signal of the vehicle, the wireless charging system charges the vehicle. The receiving end of the wireless charging system includes a logic circuit for detecting whether the electric volume of the vehicle reaches a charging standard. The wireless charging system can charge only one vehicle at one time.
In U.S. Patent Publication 2007/00019693, the position of an electronic product that is to be charged is determined through an image captured by a camera, and the electric volume of the electronic product is detected to determine whether to turn on a wireless energy transmission function. Furthermore, an optical receiver is disclosed in U.S. Pat. No. 6,972,904, wherein a diffractive optical element (DOE) is adopted for diffracting a light beam to a reflection plane, and the reflection plane is suitable for focusing the light beam into a specific direction.